Common Garter Snake

Eutaenia sirtalis, (Linn.)

General.—19 rows of scales-counted in an oblique row around the body (one variety with 17 rows). Body rather stout and with three stripes (except in one variety with which the stripes are lacking)-the side stripe on the second and third rows of scales.

Distribution.—The plains to Texas; westward to California and Washington. Occasionally, though very rarely, found in the Eastern States.

Distribution.—Western Montana, Idaho, Oregon and Washington.

Distribution.—Pacific region-California to British Columbia.

Distribution.—States east of the Mississippi.

Colouration.—The ground-colour may be brown, olive, or black. On lighter specimens the rows of spots between the stripes are well defined. The central stripe usually covers the middle row of scales and half a row on each side. This stripe may be yellow, green or whitish, and in the case of the majority of specimens is more vividly defined than the stripe on the sides as it is bordered on each side with the dark ground-colour, while the lower stripe is bordered only above by this dark hue and beneath comes in contact with a pale, brownish tinge. The latter covers the first row of scales and edges of the abdominal plates, and offers a less contrasty border than the ground-colour. On some specimens the stripes of the sides fuse into this pale band, and are thus very obscure. Such specimens show but little trace of the central stripe.(Upon such specimens has been founded the varietal name pallidula) (Allen))

Dimensions.—The measurements given represent an adult of average size:

Distribution.—The typical form of the Common Garter Snake is abundant from southern Canada to Florida (inclusive) and westward to the Mississippi. It extends yet farther westward-to the Great Plains-but in this extreme western portion of its range is not abundant.

Although the colours and pattern of this species exhibits a great amount of variation which must be classified under the head of several sub-species or varieties, the latter are not so strikingly different from the typical form as is the case with varieties of the Western garter snake, E. elegans. As has been mentioned in the description of the latter species, there is a confusing similarity between some of its forms and the present species. One of the principle differences to be observed, is the number of rows of scales on the body. With the Western snake the scales of the greater number of specimens are in 21 rows. The Common Garter Snake usually possesses 19 rows of scales. There is also a difference in the structure of the chin shields--figured among the illustrations.

The distinct varieties of the Common Garter Snake may be summed up in the following key:

General Habitat.-The most extensive of any species of this genus-comprising southern Canada, the entire United States and Mexico.

I. Three pale stripes on a darker ground. Scales in 19 rows. Three yellowish or greenish stripes; ground-colour brown, green, olive or black. Usually two rows of black spots between the stripes. No red on sides.

COMMON GARTER SNAKE, E. sirtalis, typical form, Distribution.--Southern Canada and the United States, east of the plains.

Three yellowish or greenish stripes; ground-colour brown, green or black. Upper row of spots between stripes fused into a band; lower row narrowly separated. Skin on the side, bright, brick red.

RED-BARRED GARTER SNAKE, E. sirtalis parietalis.

Three narrow broken greenish stripes on a jet black ground; abdomen dark green or slaty.

PICKERING'S GARTER SNAKE, E. sirtalis pickeringii.

II. Three pale stripes on a darker ground. Scales in 17 rows. Colours and pattern like the typical form. Differs in lesser number of scale rows, by the small, narrow head and generally smaller size of the adult.

NARROW-HEADED GARTER SNAKE, E. sirtalis leptocephala.

III. No stripes. Distinct rows of spots. Scales in 19 rows. Green, olive or brown, with rows of black spots, arranged in tessellated fashion.

SPOTTED GARTER SNAKE, E. sirtalis ordinatus.

The Typical Form.-The Common Garter Snake, of the Eastern States, is, in itself, extremely variable in its pattern and colours. Mature specimens are quite stout. Young individuals are rather slender. A very large specimen will measure about a yard in length.

As is the case with most of the species of this genus, the Common Garter Snake shows white, line-like spots on the skin between the scales, when the body is distended. Although the usual rows of square black spots cannot be discerned on very dark (black) specimens, the borders of such spots are always indicated by the sprinkling of the white dots or lines on the skin, a condition very apparent on a specimen with body flattened from anger, or much distended with food.

The abdomen of the typical form is greenish-white or yellow, with two rows of small, black blotches on the edges of the plates. The blotches are situated on the front edge of each plate and are slightly covered by the overlapping portion of the preceding plate. The upper lip plates (superior labials) are coloured like the abdomen and in contrast to the remaining portion of the head, which assumes the hue of the body.